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Shock. Scott G. Sagraves, MD, FACS Assistant Professor Trauma & Surgical Critical Care Associate Director of Trauma UHS of Eastern Carolina. Objectives. Define & classify shock Outline management principles Discuss goals of fluid resuscitation

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shock

Shock

Scott G. Sagraves, MD, FACS

Assistant Professor

Trauma & Surgical Critical Care

Associate Director of Trauma

UHS of Eastern Carolina

objectives
Objectives
  • Define & classify shock
  • Outline management principles
  • Discuss goals of fluid resuscitation
  • Understand the concepts of oxygen supply and demand in managing shock.
  • Describe the physiologic effects of vasopressors and inotropic agents
goals
Goals
  • Review hemodynamic techniques in the ICU
  • Introduce the concept of the cardiac cycle
  • Review of the pulmonary artery catheter parameters
  • Utilize the presentation to analyze clinical cases and to feel comfortable with pa-c parameters.
shock1

Shock:

“A momentary pause in the act of death.”

-John Collins Warren, 1800s

hypotension
Hypotension
  • In Adults:
    • systolic BP  90 mm Hg
    • mean arterial pressure  60 mm Hg
    •  systolic BP > 40 mm Hg from the patient’s baseline pressure
definition
Definition

SHOCK: inadequate organ perfusion to meet the tissue’s oxygenation demand.

hypoperfusion can be present in the absence of significant hypotension

“Hypoperfusion can be present in the absence of significant hypotension.”

-fccs course

pathophysiology
Pathophysiology

ATP + H2O  ADP + Pi + H+ + Energy

Acidosis results from the accumulation of acid when during anaerobic metabolism the creation of ATP from ADP is slowed.

H+ shift extracellularly and a metabolic acidosis develops

pathophysiology1
Pathophysiology
  • ATP production fails, the Na+/K+ pump fails resulting in the inability to correct the cell electronic potential.
  • Cell swelling occurs leading to rupture and death.
  • Oxidative Phosphorylation stops & anaerobic metabolism begins leading to lactic acid production.
why monitor
Why Monitor?
  • Essential to understanding their disease
  • Describe the patient’s physiologic status
  • Facilitates diagnosis and treatment of shock
history
History
  • 1960’s
    • low BP = shock; MSOF resulted after BP restored
  • 1970’s
    • Swan & Ganz - flow-directed catheter
    • thermistor  cardiac output
  • 1980’s
    • resuscitation based on oxygen delivery, consumption & oxygen transport balance.
pulmonary artery catheter1
Pulmonary Artery Catheter
  • INDICATIONS
    • volume status
    • cardiac status
  • COMPLICATIONS
    • technical
    • anatomic
    • physiologic
west s lung zones
West’s Lung Zones
  • Zone I - PA > Pa > Pv
  • Zone II - Pa > PA > Pv
  • Zone III - Pa > Pv > PA
  • PA = alveolar
  • Pa = pulmonary artery
  • Pv = pulmonary vein
standard parameters
Measured

Blood pressure

Pulmonary A. pressure

Heart rate

Cardiac Output

Stroke volume

Wedge pressure

CVP

Calculated

Mean BP

Mean PAP

Cardiac Index

Stroke volume index

SVRI

LVSWI

BSA

Standard Parameters
why index
Why Index?
  • Body habitus and size is individual
  • Inter-patient variability does not allow “normal” ranges
  • “Indexing” to patient with BSA allows for reproducible standard
index example
PATIENT A

60 yo male

50 kg

CO = 4.0 L/min

BSA = 1.86

CI = 2.4 L/min/m2

PATIENT B

60 yo male

150 kg

CO = 4.0 L/min

BSA = 2.64

CI = 1.5 L/min/m2

Index Example
pa insertion
PA Insertion

20

15

10

5

PA 19/10

PAOP = 9

RA = 5

RV = 22/4

0

slide21
CVP
  • CVP of SVC at level of right atrium
  • pre-load “assessment”
  • normal 4 - 10 mm Hg
  • limited value
slide22
PAOP
  • End expiration
  • Reflection changes with positive pressure
  • Waveforms change  every 20 cm
waveform analysis
Waveform Analysis
  • A wave - atrial systole
  • C wave - tricuspid valve closure @ ventricular systole
  • V wave - venous filling of right atrium
cardiac cycle
Cardiac Cycle

PVRI

MPAP

pulmonary

PCWP

Right ventricle

Left ventricle

RVSWI

LVSWI

MAP

CVP

systemic

SVRI

hemodynamic calculations
Hemodynamic Calculations

ParameterNormal

Cardiac Index (CI) 2.8 - 4.2

Stroke Volume Index (SVI) 30 - 65

Sys Vasc Resistance Index (SVRI) 1600 - 2400

Left Vent Stroke Work Index (LVSWI) 43 - 62

cardiac index
Cardiac Index

C.I. = HR x SVI

SVI measures the amount of blood ejected by the ventricle with each cardiac contraction.

Total blood flow = beats per minute x blood volume ejected per beat

vascular resistance index
SYSTEMIC (SVRI)

MAP - CVP

CI

 SVR = vasoconstriction

 SVR = vasodilation

PULMONARY (PVRI)

MPAP - PAOP

CI

PVR = constriction

PE, hypoxia

Vascular Resistance Index

x 80

x 80

Vascular resistance = change in pressure/blood flow

stroke work
Stroke Work

LVSWI = (MAP-PAOP) x SVI x 0.0136

normal = 43 - 62

VSWI describe how well the ventricles are contracting and can be used to identify patients who have poor cardiac function.

ventricular stroke work =  pressure x vol. ejected

definitions
Definitions
  • O2 Delivery - volume of gaseous O2 delivered to the LV/min.
  • O2 Consumption - volume of gaseous O2 which is actually used by the tissue/min.
  • O2 Demand - volume of O2 actually needed by the tissues to function in an aerobic manner

Demand > consumption = anaerobic metabolism

rationale for improving o 2 delivery
Rationale for Improving O2 Delivery

Insult

Tissue Hypoxia

Demands are met

Increased Delivery

Increased Consumption

critical o 2 delivery
Critical O2 Delivery

VO2I

The critical value is variable

& is dependent upon the patient, disease, and the metabolic demands of the patient.

DO2I

oxygen calculations
Arterial Oxygen Content (CaO2)

Venous Oxygen Content (CvO2)

Arteriovenous Oxygen Difference (avDO2)

Delivery (O2AVI)

Consumption (VO2I)

Efficiency of the oxygenation of blood and the rates of oxygen delivery and consumption

Oxygen Calculations
arterial oxygen content
Arterial Oxygen Content

CaO2 = (1.34 x Hgb x SaO2) + (PaO2 x 0.0031)

If low, check hemoglobin or pulmonary gas exchange

arteriovenous oxygen difference
Arteriovenous Oxygen Difference

avDO2 = CaO2 - CvO2

Values > 5.6 suggests more complete tissue oxygen extraction, typically seen in shock

oxygen delivery do 2 i
Oxygen Delivery (DO2I)

O2AVI = CI x CaO2 x 10

Normal values suggests that the heart & lungs are working efficiently to provide oxygen to the tissues.

< 400 is bad sign

oxygen consumption
Oxygen Consumption

VO2I = CI x (CaO2 - CvO2)

If VO2I < 100 suggest tissues are not getting enough oxygen

svo 2
SvO2

VO2

SvO2 =

1-

DO2

resuscitation goals
Resuscitation Goals
  • CI = 4.5 L/min/m2
  • DO2I = 600 mL/min/m2
  • VO2I = 170 mL/min/m2

NOT ALL PATIENTS CAN ACHIEVE THESE GOALS

Critically ill patients who can respond to their disease states by

spontaneously or artificially meeting these goals do show a

better survival.

signs of organ hypoperfusion
Signs of Organ Hypoperfusion
  • Mental Status Changes
  • Oliguria
  • Lactic Acidosis
categories of shock
Categories of Shock
  • HYPOVOLEMIC
  • CARDIOGENIC
  • DISTRIBUTIVE
  • OBSTRUCTIVE
goals of shock resuscitation
Goals of Shock Resuscitation
  • Restore blood pressure
  • Normalize systemic perfusion
  • Preserve organ function
hypovolemic shock
Causes

hemorrhage

vomiting

diarrhea

dehydration

third-space loss

burns

Signs

 cardiac output

 PAOP

 SVR

Hypovolemic Shock
treatment hypovolemic
Treatment - Hypovolemic
  • Reverse hypovolemia vs. hemorrhage control
  • Crystalloid vs. Colloid
  • PASG role?
  • Pressors?
resuscitation
Resuscitation
  • Transport times < 15 minutes showed pre-hospital fluids were ineffective, however, if transport time > 100 minutes fluid was beneficial.
  • Penetrating torso trauma benefited from limited resuscitation prior to bleeding control. Not applicable to BLUNT victims.
fluid administration
Fluid Administration
  • 1 L crystalloid  250 ml colloid
  • crystalloids are cheaper
  • blood must supplement either
  • FFP for coagulopathy, NOT volume
  • Watch for hyperchloremic metabolic acidosis when large volumes of NaCl are infused
  • NO survival benefit with colloids
role of pasg
Roleof PASG?
  • Houston - Higher mortality rate in penetrating thoracic, cardiac trauma
  • No benefit in penetrating cardiac trauma
  • Role undefined in rural, blunt trauma
  • Splinting role
cardiogenic shock
Cardiogenic Shock
  • Cause
    • defect in cardiac function
  • Signs
    •  cardiac output
    •  PAOP
    •  SVR
    •  left ventricular stroke work (LVSW)
coronary perfusion pressure
Coronary Perfusion Pressure

Coronary PP = DBP - PAOP

coronary perfusion =  P across coronary a.

GOAL - Coronary PP > 50 mm Hg

the failing heart
The Failing Heart
  • Improve myocardial function, C.I. < 3.5 is a risk factor, 2.5 may be sufficient.
  • Fluids first, then cautious pressors
  • Remember aortic DIASTOLIC pressures drives coronary perfusion (DBP-PAOP = Coronary Perfusion Pressure)
  • If inotropes and vasopressors fail, intra-aortic balloon pump
distributive shock
Distributive Shock
  • Types
    • Sepsis
    • Anaphylactic
    • Acute adrenal insufficiency
    • Neurogenic
  • Signs
    • ± cardiac output
    •  PAOP
    • SVR
sirs distributive shock
SIRS - Distributive Shock
  • Prompt volume replacement - fill the tank
  • Early antibiotic administration - treat the cause
  • Inotropes - first try Dopamine
  • If MAP < 60
    • Dopamine = 2 - 3 g/kg/min
    • Norepinephrine = titrate (1-100 g/min)
  • R/O missed injury
adrenal crisis distributive shock
Adrenal Crisis Distributive Shock
  • Causes
    • Autoimmune adrenalitis
    • Adrenal apoplexy = B hemorrhage or infarct
    • heparin may predispose
  • Steroids may be lifesaving in the patient who is unresponsive to fluids, inotropic, and vasopressor support. Which one?
obstructive shock
Obstructive Shock
  • Causes
    • Cardiac Tamponade
    • Tension Pneumothorax
    • Massive Pulmonary Embolus
  • Signs
    •  cardiac output
    •  PAOP
    •  SVR
endpoints
Endpoints?
  • ACS CoT ATLS - restoration of vital signs and evidence of end-organ perfusion
  • Swan-guided resuscitation
    • C.I.  4.5, DO2I  670, VO2I  166
  • Lactic Acid clearance
  • Gastric pH
summary
Summary

Type PAOP C.O. SVR

HYPOVOLEMIC 

CARDIOGENIC 

DISTRIBUTIVE  or N varies 

OBSTRUCTIVE   

vasopressor agents
Vasopressor Agents?
  • Augments contractility, after preload established, thus improving cardiac output.
  • Risk tachycardia and increased myocardial oxygen consumption if used too soon
  • Rationale, increased C.I. improves global perfusion
vasopressors inotropic agents
Dopamine

Dobutamine

Norepinephrine

Epinephrine

Amrinone

Vasopressors & Inotropic Agents
dopamine
Dopamine
  • Low dose (0.5 - 2 g/kg/min) = dopaminergic
  • Moderate dose (3-10 g/kg/min) = -effects
  • High dose (> 10 g/kg/min) = -effects
  • SIDE EFFECTS
    • tachycardia
    • > 20 g/kg/min  to norepinephrine
dobutamine
Dobutamine
  • -agonist
  • 5 - 20 g/kg/min
  • potent inotrope, variable chronotrope
  • caution in hypotension (inadequate volume) may precipitate tachycardia or worsen hypotension
norepinephrine
Norepinephrine
  • Potent -adrenergic vasopressor
  • Some -adrenergic, inotropic, chronotropic
  • Dose 1 - 100 g/min
  • Unproven effect with low-dose dopamine to protect renal and mesenteric flow.
epinephrine
Epinephrine
  • - and -adrenergic effects
  • potent inotrope and chronotrope
  • dose 1 - 10 g/min
  • increases myocardial oxygen consumption particularly in coronary heart disease
amrinone
Amrinone
  • Phosphodiesterase inhibitor, positive inotropic and vasodilatory effects
  • increased cardiac stroke output without an increase in cardiac stroke work
  • most often added with dobutamine as a second agent
  • load dose = 0.75 -1.5 mg/kg  5 - 10 g/kg/min drip
  • main side-effect - thrombocytopenia
slide70

Dilators

- inotropes

+ inotropes

Pressors

summary pressors inotropes
Summary `pressors & inotropes

dilator

Dobutamine

Milrinone/Amrinone

Labetalol

Ca+2 blocker

ACE inhibitor

hydralazine

nitroglycerine

Nipride

-dopamine

Isuprel

Digoxin

Calcium

-blocker

- inotrope

+ inotrope

epinephrine

-dopamine

norepinephrine

pressor

neosynephrine

slide73
GSW
  • 24 year old male victim of a shotgun blast to his right lower quadrant/groin at close range.
  • Hemodynamically unstable in the field and his right lower extremity was cool and pulseless upon arrival to the trauma resuscitation area.
post op
Post-op
  • Patient received 12 L crystalloid, 15 units of blood, 6 units of FFP, and 2 6 packs of platelets.
  • HR 130, BP 96/48, T 34.7° C
  • PAWP 8, CVP 6, CI 4.2, SVRI 2700, LVSWI 42.

Diagnosis? Treatment?

shock hypovolemia
SHOCK/HYPOVOLEMIA
  • FLUIDS… FLUIDS… FLUIDS…
  • BLOOD & PRODUCTS TRANSFUSION
  • CORRECT
    • ACIDOSIS
    • COAGULOPATHY
    • HYPOTHERMIA
slide77
MVC
  • 38 year old female restrained driver who was involved in a high speed MVC.
  • She sustained a pulmonary contusion and fractured pelvis.
icu course
ICU Course
  • Intubated and monitored with PA-C
  • PCWP = 22, CI = 3.5, SVRI = 2400, LVSWI = 39.8
  • HR = 120, BP = 110/56, SpO2 = 91, UOP = 25 cc/hr

What do you think...

hypovolemia

HYPOVOLEMIA

ADJUST YOUR WEDGE FOR THE PEEP

wedge adjustment
Wedge Adjustment
  • Measured PAOP - ½ PEEP = “real PAOP”
  • PEEP = 28, therefore “real wedge” = 8
auto pedestrian crash
Auto-Pedestrian Crash
  • Thrown from the rear bed of pick up truck during a MVC at 60 mph.
  • Hemodynamically unstable
  • Pain to palpation of the pelvis
  • Hematuria with Foley® insertion
icu course1
ICU Course
  • Pelvis “closed”
  • QID Dressings, intubated, PA-C inserted
  • PCWP = 20, CI = 5.2, SVRI = 280, LVSWI = 24.5, PEEP = 8

Diagnosis? Treatment?

sepsis
Sepsis
  • Fluids
  • Correct the cause
  • Antibiotics
  • Debridement
  • Vasopressors
    • Phenylephrine
    • Levophed
initial resuscitation
Initial Resuscitation
  • CVP: 8- 12 mm Hg
  • MAP  65 mm Hg
  • UOP  0.5 cc/kg/hr
  • Mixed venous Oxygen Sat  70%
  • Consider:
    • Transfusion to Hgb  10
    • Dobutamine up to 20 g/kg/min
vasopressors
Vasopressors
  • Assure adequate fluid volume
  • Administer via CVL
  • Do not use dopamine for renal protection
  • Requires arterial line placement
  • Vasopressin:
    • Refractory shock
    • Infusion rate 0.01 – 0.04 Units/min
steroid use in sepsis
Steroid Use in Sepsis
  • Refractory shock 200-300 mg/day of hydrocortisone in divided doses for 7 days
  • ACTH test
  • Once septic shock resolves, taper dose
  • Add fludrocortisone 50 g po q day
geriatric trauma
Geriatric Trauma
  • 70 year old female
  • MVC while talking on her cell phone
  • ruptured diaphragm and spleen s/p OR
  • Intubated and PA-C
icu course2
ICU Course
  • PCWP = 28, CI = 1.8, SVRI = 3150, LVSWI = 20.7

Diagnosis? Treatment?

cardiogenic shock1
Cardiogenic Shock
  • Preload augmentation - Consider Fluids
  • Contractility
    • dopamine
    • dobutamine
    • phosphodiesterase inhibitor
  • Afterload reduction
    • nitroglycerin
    • dobutamine
don t forget

Don’t forget...

Shock: “rude unhinging of the machinery of life.”

-Samuel D. Gross, 1872

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